NERVES OF LOWER LIMB AND THEIR INJURIES



NERVES OF LOWER LIMB AND THEIR INJURIES

LEARNING OBJECTIVES

At the end of lecture students should be able to

Know the names of nerves and their main branches innervating lower limb

Know the nerves closely related to a bone or other structure of lower limb

Know the main nerves commonly vulnerable to injury

Know the main area and loss of function if particular nerve is injured

Define and under stand terms neuritis, anesthesia, par aesthesia, paralysis, neuralgia, sciatica

LECTURE OUTLINE

NERVES OF LOWER LIMB

Arise from lumbar and sacral plexus

Main nerves of lumbar plexus are

1. Femoral nerve

2. Obturator nerve

3. Lateral cutaneous nerve of thigh

Main nerves of sacral plexus are

1. Superior gluteal nerve

2. Inferior gluteal nerve

3. Pudendal nerve

4. Sciatic nerve which terminates in popliteal fossa into

a. Tibial nerve

b. Common peroneal nerve

FEMORAL NERVE L2,3,4

Branch of lumbar plexus

Nerve of anterior compartment of thigh

Arise in abdomen, Enters thigh behind inguinal ligament lateral to femoral artery, 2 inch below inguinal ligament divides into anterior and posterior divisions

Anterior division

Muscular branches sartorius, Pectineus

Cutaneous

Medial cutaneous nerve of thigh

Intermediate cutaneous nerve of thigh

Posterior division

Cutaneous --Saphenous nerve---skin of Anteromedial surface of leg, medial border of foot upto ball of great toe

Muscular – quadriceps femoris

Articular to hip and knee joint

FEMORAL NERVE INJURY

Complete division is rare

Injured by stab or gunshot wound

Muscles paralyzed

Quadriceps femoris

Motor loss

Loss of knee extension

Sensory loss

On anterior and medial aspect of thigh

Medial side of lower leg

Medial border of foot upto ball of great toe

OBTURATOR NERVE

OBTURATOR NERVE INJURY

Causes

Penetrating wounds

Anterior dislocation of hip joint

Obturator hernia

Muscles paralyzed

All the adductor muscles except for hamstring part of adductor magnus

Motor loss

adduction of thigh

Sensory loss

Medial side of thigh

LATERAL CUTANEOUS NERVE OF THIGH L2,3

Branch of lumbar plexus

Enter thigh behind lateral end of inguinal ligament

Divides into anterior and posterior branches

Distribution

Lateral aspect of thigh and knee

Lower lateral quadrant of gluteal region

INJURY OF LATERAL CUTANEOUS NERVE OF THIGH L2,3

Causes

Compression or inflammation

Presentation

Sharp pain in the course of distribution

SUPERIOR GLUTEAL NERVE

Branch of sacral plexus

Enters gluteal region from pelvis through greater sciatic foramen above piriformis

Runs between gluteus medius and minimus

Muscles innervated

Gluteus medius

Gluteus minimus

Tensor fascia lata

INJURY TO SUPERIOR GLUTEAL NERVE

Muscles paralyzed

Gluteus medius

Gluteus minimus

Motor loss

Loss of abduction of hip

Unilateral injury shows lipping gait and positive trendelenberg,s sign i.e. Drooping of pelvis on one side when ipsilateral foot is lifted off the ground

Bilateral injury shows waddling gait

INFERIOR GLUTEAL NERVE

Inferior gluteal nerve

Branch of sacral plexus

Enter gluteal region from pelvis through greater sciatic foramen below piriformis

Runs between gluteus maximus and medius

Muscle innervated

Gluteus maximus

INJURY TO INFERIOR GLUTEAL NERVE

Muscle paralyzed

Gluteus maximus muscle

Motor loss

Impairment of hip extension and lateral rotation

Difficulty in raising the body from sitting or stooping position

SCIATIC NERVE INJURY

Commonly injured in following conditions

I.V.Disc Prolapse

Dislocation of hip joint

Piriformis syndrome

Intramuscular injection

Penetrating wound and fracture of pelvis

Most lesions are incomplete

90% cases involve common peroneal due to superficial position

SCIATIC NERVE INJURY IN INTERVERTEBRAL DISC PROLAPSE

SCIATIC NERVE INJURY IN MISPLACED INTRA GLUTEAL INJECTION

Intramuscular injections are usually given in gluteus maximus

Sciatic nerve passes midway between greater trochanter and ischial tuberosity

To avoid injury to sciatic nerve, injection should be given in upper outer quadrant

SCIATIC NERVE AND PIRIFORMIS SYNDROME

Certain leg positions pull the piriformis up against the sciatic nerve causing buttock pain & radiating leg pain

SCIATIC NERVE INJURY IN DISLOCATION OF HIP JOINT

Sciatic nerve travels in gluteal region on the posterior surface of hip joint

Prone to injury in posterior dislocation of hip joint

SCIATIC NERVE INJURY

Muscles

hamstring muscles and all the muscles below knee;

Motor loss

Severe impairment in knee flexion

Loss of all movements at foot

Deformity

foot drop due to weight of foot.

SCIATIC NERVE INJURY

Sensory loss

All sensation below knee below the knee except the medial aspect of leg and foot upto ball of big toe.

Loss of sensation of sole makes the patient vulnerable to trophic ulcers

SCIATICA

Pain along the sensory distribution of sciatic nerve

Posterior aspect of thigh

Posterior and lateral sides of leg

Lateral part of foot

Causes

Prolapse of intervertebral disc

Intrapelvic tumor

Inflammation of sciatic nerve

INJURY TO COMMON PERONEAL NERVE

Cause

Fracture of fibular neck, entrapment by leg casts or splints

Muscles paralyzed

Anterior and lateral muscles of leg

Deformity

Equinovarus-- foot is plantar flexed and inverted due to actions of unopposed plantar flexors and invertors.

INJURY TO COMMON PERONEAL NERVE

Sensory loss

Anterior and lateral side of leg

Dorsum of foot and digits

Medial side of big toe

Lateral border of foot and lateral side of little toe along with medial border upto the ball of great toe is unaffected

INJURY TO TIBIAL NERVE

Cause

Rarely injured in fractures of upper end of tibia or penetrating wound

Muscle paralyzed

All muscles of back of leg and sole

Deformity

Calcaneovulgus Dorsiflexion and Eversion of foot

INJURY TO TIBIAL NERVE

Sensory loss

Whole of the sole of foot

May result into trophic ulcers

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